KR101502184B1 - Single-phase single-phase Li insertion / extraction substance for use in Li-based batteries - Google Patents

Abstract

The invention relates to active materials for the manufacture of Li-based batteries. A crystalline nanometric powdered material with formula Lix(M, M′)PO4, in particular LixFePO4 (0≰x≰1), is disclosed, exhibiting single phase Li insertion/extraction mechanism at room temperature when used as positive electrode material in Li-based batteries. Compared to current LiFePO4, the novel material results in smooth, sloping charge/discharge voltage curves, greatly simplifying the monitoring of the state of charge of the batteries. The coexistence of mixed valence states for Fe (i.e. FeIIIVFeII) is believed to increase the electronic conductivity in the room temperature single phase LixFePO4 material, compared to state of the art two-phase materials. This, together with the nanometric size of the particles and their sharp monomodal size distribution, contributes to the exceptional high-rate capability demonstrated in batteries.

Description

Field of the Invention [0001] The present invention relates to a single-phase single-phase Li insertion / extraction material for use in Li-based batteries,

The present invention relates to a Li _x FePO ₄ (O? _X ? L) powder which exhibits a unique single phase Li insertion / extraction mechanism at room temperature (25 ° C) when used as an anode material in crystalline nano-scale materials, particularly Li-based batteries.

The first study by Padhi et al. [J. Electrochem. Soc., 144, 1188 (1997)] and a few years later, as a potential candidate as a positive electrode for rechargeable lithium batteries, phospho-olivines LiMPO ₄ Is Fe, Mn, Co ...). For example, a smart process with a carbon coating can extract Li ⁺ ions from LiFePO ₄ to yield a room temperature capacity approaching 160 mAh / g, ie, the theoretical capacity of 170 mAh / g. Room temperature Li insertion / extraction is for two-phase reactions between LiFePO ₄ and FePO ₄ to proceed at 3.45 V for Li ⁺ / Li and is well known in, for example, WO 2004/001881.

Various carbon-coated LiFePO ₄ compound tests were collected and tested according to Striebel et al. [J. Electrochem. Soc., 152, A664 (2005)], even though the matrix conductivity is improved by coating, battery developers will welcome compounds that are not present until now with a primary particle size in the range of 50-100 nm , It should also be noted that there is generally an attempt to minimize the particle size distribution to yield better power efficiency.

WO2004 / 056702 and WO2007 / 00251 teach techniques for reducing average particle size below 140-150 nm. Nonetheless, those of ordinary skill in the art acknowledge that by lowering the particle size below this value, the high power performance can be further increased.

Several researchers, for example, Yamada et al. [Electrochem. Solid State Let., 8, A409 (2005)] and US 2007/0031732 show that reducing the particle size can cause some deformation from well-described two-phase Li insertion / extraction properties. Indeed, materials exhibiting small particle size exhibit some limited solid solution (i.e., single phase) regions at room temperature, Li-deficient Li _x FePO ₄ (x < 0.15) and Li-rich Li _y FePO ₄ (y> 0.85). The x and y limits representing the boundaries of the two-phase domains may vary depending on both the specific synthesis conditions and the particle size, but no material with a very broad single phase region was obtained.

The recent discovery of a single phase Li _x FePO ₄ (O? _X ? L) solid solution at a temperature of about 350 ° C has been a very important stimulus for evaluating its role in the performance of LiFePO ₄ as a cathode material for Li- . Nonetheless, whatever the x value, it is clear that the solid solution is not stable at room temperature and therefore has limited practicality as a standard battery material [Delacourt et al., Nature Mat., 4, 254 (2005); Dodd et al., Electrochem. Solid State Let., 9, A151 (2006)].

The most obvious difference between the single phase and the two-phase insertion / extraction mechanism is that the equilibrium potential of the two-phase system is constant over the entire composition range, whereas the equilibrium potential (EMF) of the single phase system is composition-dependent. Thus, a single phase electrode will exhibit a sloping voltage curve during a charge or discharge cycle; This is preferred by the battery manufacturer because it can monitor the charge status at a reduced cost compared to a system that exhibits a flat voltage curve.

In addition, the two terminal members in the two-phase system LiFePO ₄ / FePO ₄ exhibit very limited electronic conductivity, and the mixed valence state in FePO ₄ (Fe ^(III) ) or LiFePO ₄ (Fe ^(II ) Is currently not recognized [Delacourt et al., Electrochem. Soc., 152, A913 (2005)]. As Chiang et al. In US2007 / 0031732 emphasize, the greater the number of both Fe species at all points within the deintercalation range, the higher the electronic conductivity in the material. Good material conductivity is particularly advantageous for high drain applications.

Li battery, for example, LiMnPO _4, and Li (Fe, M) as the same requirements for the enhanced conductivity material respectively as reported in Patent Application No. WO2008-77447 and 77448 PO ₄ (wherein M is Co and / or Mn Im) for Applicable to similar active substances.

In the US2006 / 0035150 Al and dissolving a source of Li, Fe and phosphate in the manufacture of coated LiFePO ₄ in the polycarboxylic acid and polyhydric alcohol together with an aqueous solution. When the water is evaporated, a mixed precipitate containing Li, Fe and phosphate is formed and polyesterification occurs. The resin-encapsulated mixture is then heat treated at 700 [deg.] C in a reducing atmosphere.

WO 2007/000251 Al describes a direct precipitation method for producing crystalline LiFePO ₄ powder, comprising the steps of:

- providing a water-based mixture of pH 6 to 10 containing precursor components Li ^(I) , Fe ^(II) and P ^(V) and a water-miscible boiling point elevation additive; And

- heating said aqueous mixture to a temperature below its boiling point at atmospheric pressure to precipitate crystalline LiFePO ₄ powder.

A very fine 50 to 200 nm particle size with narrow distribution is obtained.

US 2004/0175614 Al discloses a process for preparing LiFePO ₄ comprising the following steps:

Providing an equimolar aqueous solution of Li ^{1 +} , Fe ^{3 +} and PO ₄ ^3- ;

- evaporating water from said solution to produce a solid mixture;

- decomposing the solid mixture at a temperature below 500 ° C to form pure homogeneous Li and Fe phosphate precursors; And

- Annealing the precursor at a temperature of less than 800 ° C in a reducing atmosphere to form LiFePO ₄ powder.

The particle size of the obtained powder is 1 占 퐉 or less.

Solid State Ionics 173 (2004) 113-118 of Delacourt et al. Discloses thermodynamic and kinetic mechanisms dominating pure powder precipitation on phosphate for Li batteries. The optimum electrode is synthesized through a chemically conductive carbon coating on the LiFePO ₄ surface prepared by evaporation of Fe ^III - containing aqueous solution.

It is an object of the present invention to provide a material having a conductivity higher than the conductivity of a conventional material and to solve the problem of monitoring the state of charge.

Wherein M is at least one cation selected from the group consisting of Mn, Fe, Co, Ni, and Cu, and wherein the active component comprises Li _x (M, M ') PO ₄ M 'is an optional substitutional cation selected from the group consisting of Na, Mg, Ca, Ti, Zr, V, Nb, Cr, Zn, An insert / extract material is disclosed which is characterized by being a single phase material thermodynamically stable at 25 占 폚 during Li insertion / extraction, for x varying from 0.2 to 0.8. In the above formula, M is preferably Fe; It is also recommended that the molar ratio of M to M 'be 5 or more, preferably 8 or more. When M is Fe and M / M '> 5, the material of the present invention typically has a crystallographic cell volume of less than 291 Å, preferably less than 290 Å, more preferably less than 289 Å. The volume is deduced from XRD measurements using the Pmna or Pmnb space group.

The material of the present invention is a powder having a preferred particle size distribution d50 of 50 nm or less, preferably 10 to 50 nm. d99 is preferably 300 nm or less, preferably 200 nm or less. Also, a mono-modal particle size distribution with a (d90-d10) / d50 of less than or equal to 1.5, preferably less than or equal to 1.2 is recommended.

Another aspect of the present invention relates to a method of synthesizing the Li _x (M, M ') PO ₄ material described above. The method comprises the steps of:

Providing a first aqueous mixture of pH 6 to 10 containing Li and P precursors introduced as Li ^(I) and P ^(V) , and a bipolar (i.e., water-miscible) non-protonic additive;

Adding M ' precursor and M precursor as M ^(II) to said first aqueous mixture to obtain a second aqueous mixture; And

- heating said second aqueous mixture to a temperature below its boiling point at atmospheric pressure to precipitate the powdered Li insertion / extraction material.

In a preferred embodiment Li ^(I) is introduced as LiOH.H ₂ O and P ^(V) is introduced as H ₃ PO ₄ . It is appropriate to adjust the pH of the first mixture using LiOH.H ₂ O and H ₃ PO ₄ in appropriate proportions. The method also includes the synthesis of Li _x (M, M ') PO ₄ wherein M = Fe, M' is absent and the pH of the first aqueous mixture is 6.5 to 8, preferably 6.5 to 7.5 .

It is preferable to select and administer a bipolar aprotic additive to raise the atmospheric boiling point of the second aqueous mixture to 100 to 150 캜, preferably 105 to 120 캜. Dimethyl sulfoxide is a preferred additive. The first aqueous mixture contains 5 to 50 mol%, preferably 10 to 30 mol%, of dimethylsulfoxide.

In a more preferred embodiment, the precipitated powdery Li intercalation / extraction material is thermally post-treated by heating it at a temperature of 650 ° C or less, preferably 300 ° C or more, at non-oxidizing conditions.

In an even more preferred embodiment, the electron conductive material or precursor thereof is added prior to thermally post-treating at least one of the first aqueous mixture, the second aqueous mixture and the powder. The electron conductive material may preferably be carbon, in particular conductive carbon or carbon fiber, and the precursor of the electron conductive material may be a carbon-based polymerizable structure.

Yet another aspect of the present invention relates to a secondary Li-based battery comprising an anode, an electrolyte and a cathode, wherein the cathode comprises the material described above.

Yet another aspect of the present invention relates to an electrode mix for secondary Li-based batteries comprising the materials described above.

The first embodiment relates to an electrode mix for a secondary Li-based battery having a non-aqueous liquid electrolyte comprising at least 80% by weight of the substance of the present invention, and is characterized in that Li ⁺ / Li Has a reversible capacity of 75% or more of the theoretical capacity (about 170 mAh / g) when used as the active ingredient in the cathode which is cycled at 2.5 to 4.5 V for The amount of the additive (binder and carbon) in the electrode mixture may be limited to 20% by weight or less, preferably 10% by weight or less, because the mixture to be pasted on the current collector Since it does not have to be self-supporting.

The second embodiment, the non-containing at least 80% by weight of the substances of the present invention relates to an electrode mix for secondary Li-based battery has an aqueous gel similar to the polymer electrolyte, from 25 ℃ to-discharge rate of 0.1 C Li ⁺ / RTI &gt; of the theoretical capacity when used as the active ingredient in the cathode which is cycled at 2.5 to 4.5 V relative to the theoretical capacity. The amount of additive in the electrode mixture may be as high as 20% by weight in this case because the mixture to be rolled into sheets laminated to the current collector needs to be self-supporting during assembly of the battery of this type.

A third embodiment relates to an electrode mix for a secondary Li-based battery having a non-aqueous dry polymer electrolyte comprising at least 70% by weight of the material of the present invention, wherein Li ⁺ / Has a reversible capacity of at least 75% of the theoretical capacity when used as the active component in the cathode which is cycled at 2.5 to 4.5 V relative to Li.

A further embodiment is directed to a secondary Li-based battery having an electrode comprising as an active ingredient a nanometric powdered Li _x (M, M ') PO ₄ (O? X? L) M is at least one cation selected from the group consisting of Mn, Fe, Co, Ni and Cu; M 'is at least one cation selected from the group consisting of Na, Mg, Ca, Ti, Zr, V, Nb, Cr, Zn, And Sn, and the contribution of the electrode to the EMF of the battery at 25 DEG C is greater than 0.05 volts for x varying from 0.2 to 0.8 depending on the state of charge It is characterized by continuous change. In the above formula, M is preferably Fe; It is also recommended that the molar ratio of M to M 'be 5 or more, preferably 8 or more. When M is Fe and M / M '> 5, the nanoscale powdery active ingredient usually has a crystallographic cell volume of less than 291 Å, preferably less than 290 Å, more preferably less than 289 Å. The volume is deduced from XRD measurements using Pmna or Pmnb space groups.

"Continuously varying EMF" means a continuously sloped charge / discharge voltage curve. Such inclination according to the invention amounts to at least 5 mV per inserted / extracted Li, preferably at least 15 mV per inserted / extracted Li, which follows a full charge / discharge cycle.

The nanoscale powdered active ingredient has a preferred particle size distribution of d50 of 50 nm or less, preferably 10 to 50 nm. d99 is preferably 300 nm or less, preferably 200 nm or less. Also, a mono-modal particle size distribution with a (d90-d10) / d50 ratio of no more than 1.5, preferably no more than 1.2 is recommended.

^(I) , M ^(II) , M ' ^{(I) to (V)} , and P ^(V) for the electrical neutrality rule, while M and M' in the material of the present invention can be at least partially exchanged ^. .

A product finer than 10 nm is not particularly recommended, because it may cause processability problems during electrode production.

According to the process of the present invention, the pH of the first aqueous mixture is from 6 to 10, preferably from 6 to 8, in order to avoid precipitation of Li ₃ PO ₄ as an impurity.

A bipolar additive is used as co-solvent to reduce the size of single-phase single-phase Li insertion / extraction Li _x FePO ₄ (O? _X ? L) nano-sized particles by increasing the precipitation nucleation kinetics. In addition to being amphoteric, i.e. miscible with water, useful secondary-solvents must be aprotic, i.e. the separation caused by the release of hydrogen ions must be completely absent or very small. Co-solvents that exhibit complex or chelating properties, such as ethylene glycol, are not suitable, because they reduce the precipitation kinetics of Li _x MPO ₄ leading to larger particle sizes. Suitable bipolar aprotic solvents include dioxane, tetrahydrofuran, N- (C ₁ -C ₁₈ -alkyl) pyrrolidone, ethylene glycol dimethyl ether, C ₁ -C ₄ -alkyl of aliphatic C ₁ -C ₆ -carboxylic acid ester, C ₁ -C ₆ - dialkyl ether, an aliphatic C ₁ -C ₄ - carboxylic acid in N, N- di - (C ₁ -C ₄ - alkyl) amide, sulfolane, 1,3-di - (C ₁ -C ₈ - alkyl) -2-imidazolidinone, N- (C ₁ -C ₈ - alkyl) caprolactam, N, N, N ', N'- tetra - (C ₁ -C ₈ - alkyl) urea (C ₁ -C ₈ -alkyl) -3,4,5,6-tetrahydro-2 (1H) -pyrimidone, N, N, N ', N'- ₁ -C ₈ - alkyl) sulfamide, 4-formyl morpholine milmol, 1-piperidine or 1-formyl formate Milpitas Milpitas pyrrolidine, especially N- (C ₁ -C ₁₈ - alkyl) pyrrolidone, an aliphatic C ₁ - C ₄ - carboxylic acid in N, N- di - (C ₁ -C ₄ - alkyl) N- imide, 4-formyl morpholine milmol, 1-piperidine or 1-formyl formate Milpitas Milpitas pyrrolidine, preferably methylpiperidin (NMP), N-octylpyrrolidone, N-dodecylpyrrolidone, N, N-dimethylformamide N, N-dimethylacetamide, 4-formamorpholine, 1-formylpiperidine or 1-formylpyrrolidine, particularly preferably N-methylpyrrolidone, N, N-dimethylacetamide or hexamethylphosphoramide. Other alternatives, such as tetraalkylureas, are also possible. Mixtures of the above-mentioned bipolar aprotic solvents may also be used. In a preferred embodiment, dimethylsulfoxide (DMSO) is used as the solvent.

It can not be excluded that the new room-temperature single phase insert / extract material may induce a two-phase system at temperatures much lower than 25 캜, such as lower than 10 캜. However, this phase transition must be reversible. Therefore, its effect has only minimal impact on battery operation in most real-world environments.

The disclosed method leads to a starting material that can contain traces of Fe ^(III) . Because of the nanoscale particle size, some Fe ^(III) can arise from deviations from stoichiometry at the material surface. The presence of Fe ^(III) may also be due to grain boundaries or a second amorphous phase at the crystal surface, LiFePO ₄ (OH) or FePO ₄ .nH ₂ O. Those of ordinary skill in the art can minimize Fe ^(III) by operation under reducing atmosphere or by dependence of a reducing agent such as hydrazine or SO ₂ . A possible lack of Li in the starting material can also be compensated during the first complete discharge cycle of the battery (as in many real batteries) if the environment can provide the necessary Li.

The advantages of the materials of the present invention compared to conventional LiFePO ₄ materials are as follows:

- slope charge / discharge curves that allow you to monitor the charge status directly by simple potential measurement;

- Nanoscale particle size mitigates the kinetic limitations due to the transport of Li ions in the particles and allows fast charge / discharge of the battery;

A narrow particle size distribution results in homogeneous current distribution within the battery; This is also particularly important at high charge / discharge ratios, where fine particles can be depleted more than coarse particles, which ultimately leads to particle degradation and battery capacity fading during use; The narrow particle size distribution also facilitates the production of electrodes; And

- Fe ( ^III) / Fe ^(II) coexist, which is comparable to the conventional two-phase material represented by (lx) FePO ₄ + xLiFePO ₄ , Which is believed to increase the electronic conductivity of the room temperature single phase Li _x FePO ₄ material.

Figure 1: Constant current charge / discharge curves of the material of the present invention at 25 ° C and C / 20 rate showing a ramp curve. The plot shows the battery voltage as a function of the normalized capacity; The 0% state of charge (SOC) corresponds to the starting LiFePO ₄ material, while 100% corresponds to the charged de-lithiated FePO ₄ material.

Figure 2: FEG-SEM photograph of the Example product showing small particle size and sharp particle size distribution.

Figure 3: Example The volumetric particle size distribution and the cumulative distribution (% vs. nm) of the product are approximately 45 nm for d50, while the relative span defined by (d90-d10) / d50 is approximately 1.2 (d10 = 25 nm, d90 = 79 nm).

Figure 4: In situ XRD recorded at 25 DEG C and different charge states for the material of the present invention; 0% state of charge (SOC) corresponds to the start of LiFePO ₄ material and, on the other hand, 100% corresponds to the charged deionized Li FePO ₄ material (FePO ₄ delithiated charged material).

Figure 5: Evolution of the composition of the cell parameters in Li _x FePO ₄ (O? _X ? L) calculated from the in situ XRD recorded at different charge states and measured at 25 ° C. This clearly shows the continuous solid solution between LiFePO ₄ and FePO ₄ due to a continuous change between the limited values of the cell parameters as the lithium concentration changes from 1 to 0.

FIG. 6: Galvanostatic charge / discharge curve of conventional material state at 25 ° C and C / 20 rate exhibiting a constant voltage curve. The plot shows the battery voltage as a function of the normalized capacity; The 0% state of charge (SOC) corresponds to the starting LiFePO ₄ material, while 100% corresponds to the charged de-lithiated FePO ₄ material.

Figure 7: In situ XRD recorded at different charge states for conventional products; The 0% state of charge (SOC) corresponds to the starting LiFePO ₄ material, while 100% corresponds to the charged de-lithiated FePO ₄ material.

Figure 8: Development of the cell parameter composition in (1-x) FePO ₄ + xLiFePO ₄ (O? X? L) calculated from the in situ XRD recorded under different charge states. This clearly shows the conventional two-phase system, the ratio of each terminal member varying with the lithium concentration in the material.

The present invention is further illustrated by the following examples.

In the first step, DMSO is added to the 0.1 MH ₃ PO ₄ solution diluted with H ₂ O under stirring. The amount of DMSO is adjusted to make a global composition of 50 vol% water and 50 vol% DMSO.

In the second step, an aqueous solution of 0.3 M LiOH.H ₂ O is added at 25 캜 in a predetermined amount to raise the pH to a value between 6.5 and 7.5, leading to the precipitation of Li ₃ PO ₄ .

In the third step, a 0.1 M Fe (II) solution of FeSO ₄ .7H ₂ O is added at 25 ° C. This leads to re-dissolution of Li ₃ PO ₄ . The final Li: Fe: P ratio in the solution is close to 3: 1: 1. Controlled precipitation of Fe-species can be performed by adding the Fe (II) precursor after setting the pH of the solution to a specific value between 6.5 and 7.5, resulting in a much smaller The particle size can be obtained.

In the fourth step, the temperature of the solution is increased to the boiling point of the solvent at 108 to 110 ° C. The precipitate obtained after 6 hours is filtered and washed thoroughly with water.

The powder precipitate is pure crystalline LiFePO ₄ according to XRD measurements. The full parameter matching refinement performed on the XRD pattern (Pmnb space group) leads to cell parameters a = 10.294 Å, b = 5.964 Å and c = 4.703 Å, corresponding to a crystallographic cell volume of 288.7 Å do. The FEG-SEM photograph of FIG. 2 shows monodisperse small crystal grains in the range of 30 to 60 nm. The volume particle size distribution of the product was measured using image analysis. As shown in FIG. 3, the d50 value is about 45 nm, while the relative span defined by (d90-d10) / d50 is about 1.2 (d10 = 25 nm, d90 = 79 nm).

A slurry is prepared by mixing 10 wt% carbon black and 10 wt% PVDF in N-methylpyrrolidone (NMP) and LiFePO ₄ powder obtained by the method described above, and is deposited on an Al foil as a current collector. The obtained electrode containing 80 wt% active material is used to make a coin cell using loading of 6 mg / cm &lt; 2 &gt; active material. The cathode is made of metal Li. The coin cells are cycled in LiBF ₄ based electrolytes between 2.5 and 4.0 V. Figure 1 shows that a high reversible capacity is obtained at low rates with a sloping voltage curve showing the single phase Li insertion / extraction mechanism during cycling. It should be noted that the curve of Figure 1 was recorded under constant current conditions and therefore is close to the EMF of the electrode. In this case, the EMF continuously changes as a Li insertion / extraction function; Thus, the slope of the EMF curve is certainly not zero, though it may be slightly less than in the figures.

Figure 4 shows the in situ XRD results collected on the battery during cycling. It is evident in FIG. 5 that the insertion / extraction progresses from LiFePO ₄ to FePO ₄ with successive evolution of cell parameters, demonstrating the presence of single phase Li _x FePO ₄ (O? _X ? L). It also emphasizes good reversibility of this single phase mechanism during cycling.

Counter-example

As an opposite example, a material was synthesized according to the embodiment described in WO 2007/000251. The order of addition of the reactants is different compared to the embodiment according to the invention; It should be noted that this change is very important with respect to the final particle size of the precipitated material, the latter being about 130 to 150 nm for the precipitated product according to the prior art described above. The difference between the present invention and the prior art is that the Fe precursor is already added to a solution having a fixed pH of 6.5 to 7.5, In the prior art, the Fe-precursor is added to a solution below pH 6 and then the pH is increased to about 7 by the addition of the Li-precursor. Fe-precursors may also be added in solid form.

Characteristic analysis by Rietveld refinement from the XRD pattern showed that the crystallized cell volume of the material of the opposite example obtained was 291.7 Å.

A battery of this material was prepared as described above. Figure 6 shows charge / discharge curves of prior art materials at room temperature and C / 20 cycling rate. There is a constant voltage plateau with 2-phase Li insertion / extraction mechanism characteristics. It is emphasized that the curves of FIG. 6 were recorded under constant current conditions and thus are close to the EMF of the cell. In this case, the EMF is constant and the slope of the EMF as a Li insertion / extraction function is virtually zero.

FIG. 7 shows the in-situ XRD recorded in different charge / discharge states. The evolution of the cell parameters is shown in Fig. This clearly shows the conventional two-phase system, and the proportions of the end members FePO ₄ and LiFePO ₄ vary according to the lithium concentration in the material as opposed to the product according to the invention.

Claims (34)

As a Li insertion / extraction powder type material containing Li _x (M, M ') PO ₄ as an active ingredient, "In PO _4, and O≤x≤l, M is at least one cation selected from the group consisting of Mn, Fe, Co, Ni and Cu, the M Li _x (M, M) 'is Na, Mg, An optionally substituted cation selected from the group consisting of Ca, Ti, Zr, V, Nb, Cr, Zn, B, Al, Ga, Ge and Sn; And Characterized in that the active ingredient is a single phase material thermodynamically stable at 25 占 폚 during Li insertion / extraction, for x varying from 0.2 to 0.8. The method according to claim 1, M is Fe. 3. The method according to claim 1 or 2, Wherein the molar ratio of M to M 'is at least 5. 3. The method of claim 2, Characterized in that the crystallographic cell volume is less than 291 Å. The method according to any one of claims 1, 2, and 4, Wherein the particle size distribution (d50) is 50 nm or less. The method according to any one of claims 1, 2, and 4, Wherein the particle size distribution (d99) is 300 nm or less. The method according to any one of claims 1, 2, and 4, (d90-d10) / d50 ratio is less than or equal to 1.5. 3. The method of claim 2, Wherein the crystallographic cell volume is 290 Å or less. 3. The method of claim 2, Wherein the crystallographic cell volume is 289 Å or less. The method according to any one of claims 1, 2, and 4, Wherein the particle size distribution (d50) is from 10 to 50 nm. The method according to any one of claims 1, 2, and 4, Wherein the particle size distribution (d99) is 200 nm or less. The method according to any one of claims 1, 2, and 4, (d90-d10) / d50 ratio is 1.2 or less. A method for preparing a powdered Li insertion / extraction material according to the formula Li _x (M, M ') PO ₄ , "In PO _4, and O≤x≤l, M is at least one cation selected from the group consisting of Mn, Fe, Co, Ni and Cu, M the formula Li _x (M, M) 'is Na, Mg The method comprising the steps of: (a) providing a first electrode comprising a first electrode, a second electrode, a first electrode, a second electrode, a first electrode, a second electrode, Providing a first aqueous mixture containing a Li and P precursor introduced as Li ^(I) and P ^(V) , and a bipolar aprotic additive and having a pH of 6 to 10; - adding M precursor as M ^(II) , and M 'precursor to said first aqueous mixture to obtain a second aqueous mixture; And Heating the second aqueous mixture to a temperature below its boiling point at atmospheric pressure to precipitate the powdered Li insertion / extraction material. 14. The method of claim 13, Any or all of the Li ^(I) is characterized in that which is introduced as LiOH · H ₂ O. The method according to claim 13 or 14, Characterized in that some or all of P ^(V) is introduced as H ₃ PO ₄ . The method according to claim 13 or 14, Characterized in that the pH of the first aqueous mixture is obtained by adjusting the ratio of LiOH.H ₂ O to H ₃ PO ₄ . The method according to claim 13 or 14, M = Fe, M 'is absent, and the pH of said first aqueous mixture is between 6.5 and 8. The method according to claim 13 or 14, Wherein the bipolar non-protonic additive raises the atmospheric boiling point of the second aqueous mixture to 100-150 &lt; 0 &gt; C. The method according to claim 13 or 14, Wherein the bipolar non-protonic additive is dimethyl sulfoxide. 20. The method of claim 19, Characterized in that the first aqueous mixture contains from 5 to 50 mol% of dimethylsulfoxide. 14. The method of claim 13, Lt; RTI ID = 0.0 &gt; Li &lt; / RTI &gt; insert / extract powdery material under non-oxidizing conditions. 22. The method of claim 21, Wherein the post-treatment step is carried out at a temperature of 650 ° C or less. 14. The method of claim 13, Characterized in that the electronically conductive material or precursor thereof is added to at least one of the first aqueous mixture, the second aqueous mixture and the powder prior to the post-treatment step according to claim 21. 24. The method of claim 23, Wherein the electron conductive material is carbon. 25. The method of claim 24, Wherein the precursor of the electron conductive material is carbon-based and polymerizable. As a secondary Li-based battery, An anode, an electrolyte, and a cathode, wherein the cathode comprises the material according to any one of claims 1, 2, and 4. An electrode mix for a secondary Li-based battery, comprising a material according to any one of claims 1, 2 and 4. An electrode mix for a secondary Li-based battery having a non-aqueous liquid electrolyte comprising at least 80% by weight of a compound according to any one of claims 1, 2 and 4, Has a reversible capacity of at least 75% of the theoretical capacity when used as the active component at the cathode which is cycled at 2.5 to 4.5 V for Li ⁺ / Li at a discharge rate of 0.1 C at 25 占 폚. An electrode mix for a secondary Li-based battery having a non-aqueous gel-like polymer electrolyte comprising at least 80% by weight of a compound according to any one of claims 1, 2 and 4, Has a reversible capacity of at least 75% of the theoretical capacity when used as the active component at the cathode which is cycled at 2.5 to 4.5 V for Li ⁺ / Li at a discharge rate of 0.1 C at 25 占 폚. An electrode mix for a secondary Li-based battery having a non-aqueous dry polymer electrolyte comprising at least 70% by weight of a compound according to any one of claims 1, 2 and 4, Has a reversible capacity of at least 75% of the theoretical capacity when used as the active component at the cathode which is cycled at 2.5 to 4.5 V for Li ⁺ / Li at a discharge rate of 0.1 C at 25 占 폚. A secondary Li-based battery comprising an electrode comprising nano-sized powdery Li _x (M, M ') PO ₄ as an active ingredient, 'And at PO _4, O≤x≤l and, M is at least one cation selected from the group consisting of Mn, Fe, Co, Ni and Cu, M the nano-sized powdered Li _x (M, M)' is Wherein the cation is an optionally substituted cation selected from the group consisting of Na, Mg, Ca, Ti, Zr, V, Nb, Cr, Zn, B, Al, Ga, Ge and Sn; And Wherein the contribution of the electrode to the EMF of the battery at 25 캜 is continuously changed in accordance with the state of charge to not less than 0.05 V for x varying from 0.2 to 0.8. 32. The method of claim 31, Wherein the molar ratio of M to M 'is 5 or more. 33. The method of claim 32, M is Fe, and M 'is absent. 34. The method according to any one of claims 31 to 33, Wherein the particle size distribution (d50) of the nano-sized powdery active component is 50 nm or less.

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